1. Field of the Invention
This invention relates generally to orthopaedic appliances, and more particularly to one such appliance for support in the act of human limb manipulation such as in walking wherein the appliance enables improved motor motion.
2. Description of Related Art
The following art defines the present state of this field:
Carsalade, U.S. Pat. No. 4,617,920 describes a device for facilitating practice of downhill skiing which includes for each lower limb a knee bandage having two suitable curved and profiled plates, one of which wraps up the thigh while the other wraps down the leg, being adapted to cooperate with a part of the user's shoe; the upper plate is continued downward by two opposite and parallel arms profiled and articulated each on a shaft, on either side of the knee, the lower plate being continued upward by two opposite and parallel arms profiled and articulated around the shaft in combination with the upper plate, the lower place being controlled by elastic components to be tensioned, when flexing the knee in combination with appropriate means, designed to suppress this control beyond a certain flexion angle, said means being fastened to a manual releasing component to fully suppress the elastic control.
Vallotton, U.S. Pat. No. 4,051,558 describes an artificial leg which includes a trunk socket, a thigh section hingably coupled to the trunk socket, a leg section hingably coupled to the thigh section and a foot section hingably coupled to the leg section. A mechanical energy storage device, such as a spring, is operatively associated with the artificial leg for storage and release of energy during a normal walking stride of the user. More particularly, energy is stored in the mechanical energy storage device during a weight-bearing phase of the walking stride when the user's weight is on the artificial leg and energy is released during a phase of the normal walking stride, when the user's weight is removed from the artificial leg. The stored energy is released from the energy storage device to pivot the thigh section forwardly about the hinged coupling thereof to the trunk socket. A dash-pot is coupled between the lower end of the thigh section and the foot section for damping flexion of the knee joint after a certain predetermined extent of ankle flexion is achieved to derive a more normal stride and cadence.
Asbelle, et al., U.S. Pat. No. 3,673,613 describes a variable friction knee unit that applies independent braking forces at different times to the swing phase of an artificial leg during walking which simulates the actions and efficiencies of the quadriceps and hamstring muscles of the thigh. Two braking modes are applied with an additional continuous braking mode. One operates at each end of swing phase. The second brake is applied a few degrees after the first brake and superimposed over the first brake. Both brakes are applied at each end of the swing phase of the walking cycle. In addition to being operative at the terminus of the swing, the two brakes are engaged at different times and are superimposed over the application of continuous friction so that the deceleration is a stepping function thereby simulating the function of the quadriceps and hamstring muscles of the thigh.
Adams, et al., U.S. Pat. No. 5,092,902 describes a prosthetic leg with a pivotal knee joint and a hydraulic fluid control unit connected to provide variable forces which dampen flexion and extension of the knee and also bias the leg to its extended position. The unit includes an aluminum housing lined with an axially adjustable sleeve and control bushing defining a cylindrical chamber which receives a piston mounted on a tubular position rod. The housing and chamber receive hydraulic fluid or oil which flows during movement of the piston through fluid control ports, channel and adjustable gaps defined by the sleeve and bushing for damping the movement of the rod. The piston rod encloses a gas filled flexible bladder which forms an oil accumulator during inward movement of the piston rod and also produces variable forces for moving the piston rod outwardly to its extended position. The housing confines a gap defining ring which compensates for changes in oil viscosity with heat.
Aulie, U.S. Pat. No. 5,171,325 describes a prosthetic joint which includes an anterior linking and support member and a posterior linking and support member, forming of a resilient material, which act as cantilever flat springs to provide an intrinsic extension bias while furnishing the rigid structure necessary to support the axial loads and extension movements induced by the amputee. A prosthetic knee joint includes a base formed of a resilient polyamide such as nylon 6/6, from which an anterior linking and support member, generally of an L-shape, and a posterior linking and support member, monolithically extend upwards. Formed to provide the inherent stability of four-bar linkage, these resilient linking and support members are pivotally attached to a yoke member to act as cantilever single-leaf flat springs which provide an intrinsic extension movement to the prosthetic knee joint which may vary according to the amount of flexion of the knee joint. The extension movement of the knee joint is translated into compression at the anterior linking and support member and tension at the posterior linking and support member, thereby allowing the use of a relatively low-strength resilient material in the knee joint construction. A common double-acting hydraulic damper is used to reduce the swing rate of the knee joint, permitting a desired gait and reducing terminal impact at full extension.
Glabiszewski, U.S. Pat. No. 4,595,179 describes a hydraulic damping unit, particularly for use in artificial joints. The unit includes a cylinder housing having a screw-in bottom part. A hollow piston is guided in the housing and has on its jacket a shoulder which delimits with corresponding flanges in the inner wall of the housing two chambers of variable volume for storing a hydraulic liquid. A hollow throttling piston is guided in the main piston and is formed with an annular recess which communicates with respective variable volume chambers via passages passing through the jacket of the main piston at both sides of the shoulder. In the range of both passages, the bottom of the recess of the throttling piston is connected to the outer surface of the latter via a sloping annular surface which, depending on the relative position of the throttling piston to the main piston, adjusts the clearance of the passages to control the resistance to flow of the hydraulic liquid. A set screw is arranged in the main piston opposite the end face of the throttling piston to adjust its axial position, and a counteracting return spring is arranged inside the throttling piston. Disclosed is also an artificial joint provided with the above hydraulic damping device. The lower part of the joint has a fork-shaped configuration, and the cylinder housing of the damping device is formed with pivot pins journalled in the opposite walls of the lower part. The main piston is linked to the upper part of the joint at a point which, in the aligned position of the upper and lower parts, is below the hinge axle of the joint.
Haupt, U.S. Pat. No. 4,685,927 describes a braked knee joint having a thigh part and a lower leg part which are provided with braking surfaces adapted to one another and which, because of the capacity for axial movement of the thigh part relative to the lower leg part, are pressed against one another during loading. The braking surfaces essentially have a contour which is circular in vertical section and which has a constant radius relative to the rotational axis. The joint includes a suitable stop to produce a jerk-free termination of the extension movement of the knee joint out of the flexed position. The stop is formed by providing the braking surface of the thigh part with a front end piece which is at a distance which increases from the rotational axis and is greater than the constant radius, and by providing a corresponding front end piece of the braking surface of the lower leg part so that, with increasing extension of the knee joint in the unloaded condition, a constantly increasing area of the braking surfaces comes into frictional contact and this forms the stop.
Nader, et al., U.S. Pat. No. 3,309,715 describes a safety knee for artificial legs with brake surfaces that can be more readily adjusted in order to compensate for wear and also for various specific tasks that the amputee may wish to perform. There will be a gradual wear of the brake linings and the present invention permits the knee to be adjusted for whatever wear may occur. There are certain tasks that necessitate a more abrupt adjustment. The invention has an aim for the adjustment of the braking surfaces through the user's clothing in order to either decrease or increase the clearances between the brake surfaces. In this regard, the brake surfaces can be adjusted so as to provide sufficient clearance in order to permit complete freedom of movement, such movement being desirable when riding a bicycles, for instance. If the amputee desires a completely rigid knee, such adjustment can also be achieved, thus permitting the user to walk on uneven ground, for instance. Consequently, the present invention provides a considerable amount of versatility as far as the adjustment feature is concerned.
Haupt, U.S. Pat. No. 4,685,926 describes an arrestable knee joint, comprising of a thigh member; a lower leg member; rotatably articulated on the thigh member to form a knee joint; and a mechanism for releasably arresting the members in the extended position, comprising a spring-loaded arresting element mounted in the lower leg member, structure associated with the thigh member for engaging the arresting element when the members are in the extend position, a rocker arm assembly having a first arm attached to the arresting element and a second arm extending away from a rotational axis of the rocker arm assembly on a side opposite from the first arm, and a Bowden wire inserted into the lower leg member and attached to the second arm of the rocker arm assembly. A release mechanism is provided in the thigh member.
Weber, et al., U.S. Pat. No. 4,135,254 describes a prosthetic knee apparatus which includes a pair of spaced side brackets depending from the upper leg prosthesis, and a housing disposed between the brackets. Extending through the housing to the brackets are anterior and posterior pivot shafts, the posterior pivot being provided with some play to permit a slight degree of pivot about the anterior shaft. A pair of leg brackets are also joined to the posterior pivot shaft with no play, and the housing is provided with a locking pin arrangement to releasably lock the leg brackets to the housing. The housing is provided with a pair of opposed braking pads which impinge on the leg brackets, the braking pads being actuated by a wedge which is driven into engagement by weight applied to the upper leg portion posteriorly of the anterior pivot shaft.
Wilkes, U.S. Pat. No. 4,005,496 describes a prosthetic knee joint having a femoral member and a tibial member each of which is provided with a bearing surface. The bearing surface of the tibial member supports the bearing surface associated with the femoral member such that flexion between the tibial member and the femoral member causes the respective bearing surfaces to roll relative to one another. Rollers, cam surfaces and guide slots are provided to ensure the retention of the proper relationship for this rolling contact between the tibial bearing surface and the femoral bearing surface. The knee joint includes a mechanical brake which produces a brake force that increased with flexure between the tibial member and the femoral member. The brake includes a resilient deformable element which transmits a brake applying force to a brake shoe which is operable along an axis generally perpendicular to the direction in which the force is applied. Hyperextension of the knee joint is mechanically limited and a torsion rod accommodates torsional motion between the knee joint and a lower leg to which it may be attached. The knee joint also includes a member which simulates the movement of the patella bone of a human knee.
NASA's Marshall Space Flight Center, Huntsville, Alabama has published a monograph describing a leg supporting device entitled Dual-Position Brace, and which is abstracted in Popular Science, May 1997, p27. This monograph describes a leg brace that lets the knee bend but locks in position when weight is put on the heel of the foot. This allows rehabilitation to begin before the knee can carry the full weight of the patient.
The prior art teaches the use of mechanical aids in providing support to the human knee joint, and replacement as well, and teaches several approaches to mechanically facilitating the functional use of a damaged knee joint for walking. However, the prior art does not teach a mechanical strut appliance capable of enabling a weak leg or a leg without knee function to perform a normal walking gait. The prior art does not teach a miniature and highly compact orthotic knee joint and brace having a pressure induced brake and a means for accelerating the rotation of the lower leg into a position for taking a load. The present invention fulfills these needs and provides further related advantages as described in the following summary.